This invention relates to dynamoelectric machines such as electric motors, and more particularly, to a blocking strip for preventing flow of cooling air over a motor protector which responds to stator winding temperatures.
Dynamoelectric machines such as electric motors are typically installed in various types of household appliances as, for example, dishwashers. In operation, electric motors are subject to heat generated by the normal operation of the motor, and heat transferred to the machine from its surrounding environment. To help cool the machine, a ventilating fan may be attached to the motor shaft so to draw air through the motor, through openings in the motor housing.
At the same time, electric motors are typically provided with a protector which includes a sensor for monitoring the temperature of the stator windings. The protector acts as a circuit breaker to interrupt the energy provided the motor when the sensed temperature of the windings exceeds a predetermined temperature level.
A problem therefore arises when cooling air is being drawn through the motor because the air flow over the protector, in effect, desensitizes the protector to the stator winding temperature. This could result in the windings overheating, which, in turn reduces the useful life of the motor and could cause expensive repair to the appliance.